Without limiting the scope of the invention, the background is described in connection with existing drug delivery systems. Stimuli-responsive drug delivery systems (DDS) are highly desirable if they can be engineered to deliver a drug in spatial-, temporal- and dosage-controlled manners. Specifically, the ability to trigger delivery is expected to enable time-controlled and targeted drug delivery and to reduce required dose, minimize systemic exposure and thus reduce overall toxicity. Several concepts have been proposed for stimuli-responsive DDS including protonation, hydrolytic cleavage and (supra)molecular conformational changes. Recent advances in the design of nanoscale stimuli-responsive systems are aimed to controlling drug biodistribution in response to specific stimuli including endogenous and exogenous stimuli. Proposed endogenous stimuli include changes in pH, enzyme concentration and redox gradients. Proposed exogenous stimuli include variations in temperature, magnetic field, ultrasound intensity, electric and light pulses. To date, light responsive drug therapy has focused on use of photosensitizing compounds and photoactive compounds that generate reactive oxygen species (ROS) upon light exposure. See, e.g. Liu, D., et al. “The Smart Drug Delivery System and Its Clinical Potential” Theranostics 6 (9) (2016) 1306-1323.
Existing approaches have not provided engineered light responsive molecules that respond to light with conformational changes. From the foregoing, it appears that compositions and methods are required that enable light induced drug delivery.